1. Field of the Invention
The invention relates to a clamp unit for Do-It-Yourself (DIY) solid wood flooring, and more particularly, to a clamp which can automatically adjust its clamping structure in accordance with the expansion and contraction of the solid wood panels and is especially suited for wood flooring used to cover irregular shape floors.
2. Description of the Related Art
Solid wood flooring provides a durable surface that is widely received by house owners for its natural warmth and beauty. However, solid wood flooring is made up of separate wood panels laid side-by-side. Therefore, the gap left between each wood panel is of utmost importance and must rely on the craft and skill of the floor panel layer. If the panels are not laid properly, expansion and contraction will cause the panels to deform after a while, and the entire flooring must be changed. Because of this, labor costs are often much higher than the cost of the wood material, resulting in higher overall construction costs and additional financial burden to the user. Furthermore, floor panel layers are often hard to hire if the construction project is small or for only partial interior decoration.
As a result, DIY solid wood flooring has become increasingly popular. In order to make solid wood flooring DIY, installation methods must be easy and simple so that any consumer can lay the panels by himself. It is under these circumstances that a clamp unit for DIY solid wood flooring was invented.
FIG. 1 shows the commonly used clamp 1 for a DIY solid wood floor panel. The clamp is a square shaped piece of plastic made from a single mold that has a T-shape protrusion 11 in the center and two other protrusions 12, 13 on both sides. The installation position is shown in FIG. 2. Position the solid wood panel 2b at an angle so that its tongue 21 fits into the groove 22 of the other solid wood panel, then lay the panels flat down as shown in FIG. 3A. At this time, the clamp's 1 T-shape protrusion 11 now rests on the topside of the tongue 23 between solid wood panels 2a and 2b. Meanwhile, the protrusions 12, 13 on the two sides must fit into the grooves on the bottom side of solid wood panels 2a and 2b. 
As the aforementioned commonly used clamp 1 is made from a single mold of plastic, the clamp's 1 design concept is to join solid wood panels 2a and 2b by fitting in to the grooves found on the bottom side of solid wood panels 2a and 2b, making it easy to install, but it also has its disadvantages. For example: When solid wood panel 2b is being installed close to the wall w, the clamp's 1 additional length L must be severed and removed, as depicted in FIG. 3B where only half of the clamp 1′ is being used to support solid wood panel 2b's outer bottom. Severing is no easy task for the DIY consumer, especially since the clamp 1 is made from hard plastic material and has a slippery surface. Consumers are often hurt when trying to sever the clamp.
In addition, the other disadvantage of the aforementioned clamp 1 is shown in FIGS. 4A, B, i.e. the reserved gap left between the conjunction points T1 when solid wood panels 2a and 2b are laid together. Moreover, there are a wide variety of solid wood panels, such as pinewood, redwood, oak wood, sandalwood, etc. Due to the characteristics of each type of wood, some solid wood panels will undergo significant changes from their own expansion and contraction under different types of environment, climate, or humidity. As shown in FIG. 4B, when the gap T2 between solid wood panels 2a and 2b open up because of their contraction, then the clamp 1 will easily break at the protrusions 12, 13 due to the pressure from both sides. This will affect the overall bondage strength of the wood flooring as well as its usage life.
Referring to FIG. 5, another type of commonly used DIY clamp is in the form of clamping tracks. A plurality of clamping tracks 3 in parallel are placed on the floor. Each clamping track 3 is made up of several individual clamp units 3a, 3b, 3c, 3d, 3e . . . 3n linked together. On the right side of each individual clamp is a clamp hook 31. The solid wood panels 2a, 2b . . . 3n are then placed and installed on top of their corresponding clamp units 3a, 3b . . . 3n. 
The disadvantage to this type of clamping track 3 is that it must be laid out in parallel, i.e. it is only suited for square or rectangular shape floor spaces. Yet many homes have floor spaces that are irregularly configured circular or slanted, etc., which makes these types of clamps unsuitable. Due to its configuration limitations, these clamps are not widely used, which is one of its disadvantages. Another disadvantage of this type of clamp track 3 is shown in FIG. 6. The clamp hook 31 on each individual clamp unit 3a . . . 3n hooks only onto the right side tongue 23 of each solid wood panel 2a . . . 2n. The left side, on the other hand, has no clamp hooks. As such, there is no clamp hook on the last clamp unit 3n of the clamp track 3 to hold down the last piece of solid wood panel 2n. This allows the last solid wood panel to easily come off, leading to the problem of loose bondage between the solid wood panels.
In light of these problems, I, the inventor, have completed this invention after constant study and modifications to the commonly used clamp unit for DIY solid wood flooring.